The present invention relates to power supply systems, and more particularly, to a serial loading constant current power supply system.
Information and Communication Technology (ICT) equipment and facility have power conversion process of four to sixth steps and thereby their power efficiency is very low.
To overcome the above-mentioned the efficiency problem, Lawrence Berkeley National Laboratory carried out a study on a direct current feeding ICT power supply system. The study report issued in 2006 has claim that the power efficiency improvement is maximum 35%.
ITU-T tries to standardize a DC power feeding system standard for an information communication device to reflect the attempts to solve the problem.
However, the efforts to develop a DC power feeding technology known until now adopts a constant voltage, parallel loading scheme, similar to a conventional AC power feeding system.
One of the problems of the conventional technology is such that since a large pulsating current according to a loading status flows through a feeding line having a relatively great antenna radiation effective area, it radiates a strong electromagnetic interference (EMI) noise to disturb a normal operation of a load electronic/power device. To block out the EMI noise radiation in the power feeding system, a capacitor and an inductor which are expensive and have a large size are needed and thereby their cost increases. Also, additional costs occur to block out the EMI noise.
Another problems of the conventional technology is such that in a LED lightning being widely used these days, since the property of load itself is a constant current property, if using a conventional constant voltage power feeding, an additional power converting device converting a voltage into a current source is needed. This acts as a factor hindering an energy efficiency advantage of LED itself. Thus, overall luminous efficiency of a LED lighting including power feeding circuits has a similar level compare to the fluorescent lighting.
A high performance computer has several processors. A recent high performance individual processor requires very high fluctuating drive current. However, a drive voltage being required is about 1 Volt is very low. A voltage regulator module (VRM) being used in the high performance processor is very expensive to occupy 25˜30% of a processor price, has physically a large volume and has approximately power conversion efficiency of about 80% and thereby it has problems of price and reliability.